Hantaan virus was discovered only ten years ago, and since then has become the focus of much interest in the medical community, because of its world-wide distribution. We have cloned into expression systems the genes for the structural proteins of the virus and intend to use these clones in exploration of the functional aspects of this fascinating virus. First, several features of the structure of Hantaan glycoproteins will be investigated, including modes of synthesis and processing, the nature of the oligosaccharide residues, and the sites of glycosylation. Possible disulfide bonding will be examined and the likely association of glycoproteins into higher order structures probed. The role of these proteins in cell fusion, in infectivity and in recognition of a cellular receptor for the virus will be investigated. New constructs in eukaryotic expression systems will be made, which will include intact and mutagenised versions of the genes for structural proteins; these will be used in a variety of assays for function, including cellular localization, identification of signal and membrane anchor sequences, and cleavage sites. The many likely functions of the nucleocapsid protein, N, will be assessed. Functions include RNA-binding, self-association and association with glycoproteins. The immune responses to virus proteins will be measured, revealing immunoreactive domains responsible both for a humoral response and for cell-mediated immunity. These studies are expected to lead to a new understanding of Hantaan virus replication and to have important implications for virus pathogenesis, as well as antiviral therapy.